In all of the following, the term “journal” will be used which must be understood as being any similar part or belonging to a rotating shaft.
FIGS. 2 and 3 illustrate, schematically and in axial section, respectively two known arrangements of the assembly between a journal and a bearing inner race. In these two examples, the bearing is a roller bearing.
“Axial section” means a section taken along the longitudinal axis of the journal. In these two figures, similar elements bear similar reference numbers.
Reference number 102 indicates a journal having an axis 104. The journal 102 is supported by a bearing having a bearing inner race 106 and a bearing outer race 108. Between the bearing inner race 106 and the bearing outer race 108 there are rollers 110. The bearing outer race is attached to a fixed part 112. The bearing inner race 106 is attached to the journal 102.
FIG. 2 illustrates an assembly arrangement in which the bearing inner race 106 is attached to an end of the journal 102 by means of a weld 116.
The bearing inner race 106 forms here an extension of the journal 102. In other words, this configuration is similar to a configuration in which the rollers 110 would be directly incorporated into the journal 102.
Such an assembly arrangement by welding has disadvantages. Specifically, the bearing inner race 106 and the journal 102 are made of different materials. It is often difficult to make a firm weld between two parts made of different materials. In addition, when such a weld is made, the lifetime of the assembly is not always satisfactory.
FIG. 3 illustrates an assembly arrangement in which the bearing inner race 106 is mounted by being clamped axially against a shoulder 118 of the journal 102, and attached by means of a clamping nut 120. An anti-rotation device 122 associated with the clamping nut 120 prevents rotation of the latter relative to the journal 102.
Such a mechanical assembly by clamping nut does not have the disadvantage specific to an assembly by welding. However it has another disadvantage linked to the bulk of the assembly. Specifically, in turbomachines designed to receive such assemblies, it is increasingly necessary to limit the axial length of the journal or of the rotating shaft. The presence of the clamping nut 120 and its anti-rotation device 122 placed at the end of the journal 102 beyond the bearing inner race 106, requires the axial length of the journal 102 to be greater than the axial length of a journal 102 suitable for an assembly by welding.
An object of the present invention is to provide an assembly arrangement of an inner race and a journal that does not have the aforementioned disadvantages.
More precisely, an object of the present invention is to provide an assembly arrangement that is mechanical and that does not require an increase in the axial length of the journal.
In everything that follows, the “bearing inner race”, respectively the “bearing outer race”, will simply be called “inner race”, respectively “outer race”.